consumer surplus

[mathstresser]

A demand curve is given by p=450/(x+8). Find the consumer surplus when th seling prices $10.

I found what x should be to get 10. x=37

Then I did the integral of 450/(x+8)-10, and I got 450 ln(x+8) - 10x; evaluated from 0 to 37.

But I get $1343.00 The answer should be $407.25 What should I be doing?!?

 

[Unco]

You have forgotten to subtract (450*ln(0 + 8) +10(0)) when evaluating the definite integral (thought it was zero?).

 

[mathstresser]

yes..

I can't believe I did that...

THANK YOU!